(623an) Do Bacteria Optimize Their Contact Area with Surfaces?

Authors: 
Behkam, B., Virginia Tech
Kargar, M., Virginia Tech
Nain, A. S., Virginia Tech
Saucke, J. R., Virginia Tech


Using our previously developed Spinnert based Tunable Engineered Parameters (STEP) technique, polystyrene (PS) fibers (2Rf: 300 nm to 600 nm, length: 10 mm, 2Df: 0 nm to microns) were deposited in aligned configuration on both glass and PS substrates. Pseudomonas aeruginosa (PAO1), a common human pathogen was used as the model organism in this research. Static retention assays were conducted by placing triplicates of each sample in a suspension of bacteria in phosphate buffered saline (PBS)  with starting optical density, OD600nm = 0.3 for 2 hours at 37 oC. Five most predominant modes of interactions between the bacteria and parallel nanofibers were identified. Scanning electron microscope imaging was utilized to quantify line density (number of bacteria/fiber length) of bacteria attachment for all five possible cases. Comparing results brings this fact in focus that for surfaces with polystyrene nanofibrous features; more hydrophobic substrate promotes the modes in which bacteria prefer unaligned condition. Therefore, we conclude that favorable conditions for bacteria attachment are dependent upon two parameters: topography and hydrophobicity. It has been demonstrated that bacterial cell do not always maximize their contact area with substrate and that surface energy affect their preferred mode of interaction and attachment density. We plan to use these findings towards identifying the optimum nanofiber dimension and spacing for minimizing bacterial adhesion and biofilm formation. Finding from this work can also be used towards developing more effective nanofibrous tissue scaffolds which need to promote adhesion of mammalian cells and minimize bacterial adhesion. 
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